The Operations and Clinical Assessment Core (OCAC) fulfills the required core described in the CIDAR Program Announcement (PA05-039). The OCAC will serve three major functions: 1) overall center administration;2) subject recruitment and assessment;and 3) database management and statistical analysis. Consequently, the OCAC has been divided into three divisions corresponding with these major functions. Each division has a director specifically assigned to ensure that the goals and objectives for that division are met;these directors report to Dr. Strakowski, who will serve as OCAC director, in addition to his role as overall BITREC director. The Administrative Division will provide overall management of the BITREC; to achieve this goal it will be composed of the BITREC director, a Steering Committee, two external advisory committees and administrative personnel. Dr. Strakowski will direct this division, consistent with his roles as OCAC and BITREC director. The Clinical Assessment and Recruitment Division (CARD) of the OCAC will provide patient recruitment, informed consent and human subjects regulatory functions, and initial assessments. We have chosen to centralize these functions in order to integrate projects and to maintain consistent subject management and evaluations across projects. Dr. DelBello will direct the CARD. The Biostatistics Division (BD) is included in the OCAC as required by the CIDAR program announcement, although, given the central role of Biostatistics in this center, this division will, in many ways, function as a core. The Biostatistics Division will be a central resource used by all projects and cores. This division will provide expertise in the translation of clinical hypotheses into testable statistical hypotheses, selection of efficient study designs and measurement protocols, estimation of sample size requirements, acquisition and management of data, statistical analysis, and final report preparation. The Biostatistics Division will be codirected by Drs. Succop and Arndt. The divisions of the OCAC will provide organizing and integrating functions over all of the remaining cores and projects.